Valve just released server.dll with the coming of local play when you play the campaign and bots single player.
Though, there seems to be some problems with it at the moment and the Dota engine doesn't seem to like the modifications according to this thread: http://www.reddit.com/r/DotA2/comments/19dtyb/managed_to_load_an_altered_dota_2_maphow_to_inside/
Though, there seems to be some problems with it at the moment and the Dota engine doesn't seem to like the modifications according to this thread: http://www.reddit.com/r/DotA2/comments/19dtyb/managed_to_load_an_altered_dota_2_maphow_to_inside/